Sponsors of defined benefit and defined contribution retirement plans should keep the following deadlines and other important dates in mind as they work toward ensuring compliance for their plans in 2026. Dates assume a calendar year plan. Some deadlines may not apply, or dates may shift based on the plan sponsor’s fiscal year. For additional support, please contact your BDO representative
JANUARY
15 / Fund: Possible fourth quarter 2025 contribution due for defined benefit pension plans.
FEBRUARY
2 / Action: File IRS Form 945, Annual Return of Withheld Federal Income Tax for non-payroll income taxes, such as taxes withheld by retirement plans, during 2025.
2 / Action: Distribute IRS Form 1099-R to participants for 2025 retirement plan distributions.
10 / Action: File IRS Form 945 for 2025 non-payroll withholding if taxes were paid in full and deposited on time.
MARCH
15 / Action: Highly compensated employees who fail ADP/ACP test for prior plan year must have refunds processed by March 15 (other than eligible automatic contribution arrangements).
15 / Fund: Partnerships and S Corporations that are not getting an extension must fund employer contributions to receive tax deduction for the prior year.
31 / Action: Deadline for electronic filing of Form 1099-R with the IRS.
APRIL
1 / Action: April 1 deadline for 5% business owners and terminated participants who turned 73 in 2025 to receive their required minimum distribution (RMD).
15 / Fund: Possible first quarter 2026 contribution due for defined benefit pension plans.
15 / Distribute: Participants who contributed over 402(g) or 415 limits in the previous year must be refunded the excess amount by April 15.
15 / Action: File PBGC Form 4010, Notice of Underfunding for single-employer defined benefit plans with more than $15 million aggregate underfunding by April 15.
15 / Fund: C-Corporations and Sole Proprietors that are not getting an extension must fund employer contributions by April 15 to receive tax deduction for the prior year.
15 / Fund: IRA contributions for the prior tax year must be funded by April 15.
30 / Action: Send annual funding notice to participants of single and multi-employer defined benefit plans over 100 participants by April 30.
MAY
15 / Action: Start your mid-year compliance audit to ensure all records and documentation are up to date.
JUNE
29 / Action: 401(k) plans with publicly traded employer stock must file SEC Form 11-K with the Securities and Exchange Commission by June 29 or file an extension on SEC Form 12b-25.
30 / Action: Highly compensated employees who fail ADP/ACP test for prior plan year must have refunds processed by June 30, if an eligible automatic contribution arrangement (EACA).
JULY
14 / Action: 401(k) plans with publicly traded employer stock that requested a 15 calendar day extension (SEC Form 12b-25) for the SEC Form 11-K must file the SEC Form 11-K with the Securities and Exchange Commission by July 14.
15 / Fund: Possible second quarter 2026 contribution due for defined benefit pension plans by July 15.
31 / Action: File IRS Form 5500, Annual Return/Report of Employee Benefit Plan, and IRS Form 8955-SSA, Annual Registration Statement Identifying Separated Participants With Deferred Vested Benefits, for the 2025 plan year by July 31.
31 / Action: To request an extension of time to file IRS Form 5500, file IRS Form 5558 by July 31.
SEPTEMBER
15 / Fund: If an extension was filed, September 15 is the deadline to fund employer contributions for Partnerships and S-Corporations.
15 / Fund: Last date to make 2025 contributions for single and multiemployer defined benefit pension plans.
30 / Action: September 30, Distribute Summary Annual Report (SAR) to participants if the Form 5500 was filed on July 31.
OCTOBER
3 / Action: Distribute annual notices to participants no earlier than October 3 and no later than Dec 2, including notices for: 2027 401(k) Plan Safe Harbor Match, Automatic Contribution Arrangement Safe Harbor, Automatic Enrollment and Qualified Default Investment Alternatives (QDIA).
15 / Fund: Possible third quarter 2026 contribution due for defined benefit pension plans by October 15.
15 / Action: October 15 is the extended deadline for filing IRS Form 5500 and IRS Form 8955-SSA.
15 / Action: October 15 is the extended deadline for filing individual and C-Corp tax returns.
15 / Action: If an extension was filed, October 15 is the deadline to fund defined contribution employer contributions for C-Corporations and Sole Proprietors.
15 / Action: Send annual funding notice to participants of single and multi-employer defined benefit plans with 100 or fewer participants by October 15.
15 / Action: October 15, defined benefit plan PBGC Premium filings and payments due.
31 / Action: Single-employer defined benefit plans that are less than 60% funded or are 80% funded and have benefit restrictions triggered must inform participants by October 31 or 30 days after the benefit restriction applies.
DECEMBER
2 / Action: Distribute annual participant notices no later than December 2 for the 2027 upcoming calendar year plan year. These include notices for: 401(k) Plan Safe Harbor Match, Automatic Contribution Arrangement Safe Harbor, Automatic Enrollment and Qualified Default Investment Alternatives (QDIA).
15 / Action: December 15 is the extended deadline to distribute Summary Annual Report (SAR) when the Form 5500 was filed on October 15.
31 / Action: December 31 is the final deadline to process corrective distributions for failed ADP/ACP testing; a 10% excise tax may apply.
31 / Action: Ongoing required minimum distributions (RMDs) for 5% business owners and terminated participants must be completed by December 31.
31 / Action: Amendments to change traditional 401(k) to safe harbor design, remove safe harbor feature or change certain discretionary modifications must be completed by December 31. Amendments to change to safe harbor nonelective design must be completed by Dec 1 of given plan year for 3% or by Dec 31 of the following year for 4% contribution level.
31 / Action: Plan sponsors must amend plan documents by December 31 for any discretionary changes made during the year.
31 / Action: Deadline for plan amendments for CARES Act, SECURE 1.0 and SECURE 2.0 here for qualified plans, excluding governmental plans or union plans. Read this article for more information.
Important
In addition to those important deadlines and dates, plan sponsors should be aware of the contribution plan limits and other rolling notices for 2026:
Traditional and Roth Individual Retirement Account contribution limit is $7,500. Catch-up contributions for participants age 50 and over is $1,100, which is fixed by law and not adjusted each year.
Employee salary deferral limit for 401(k), 403(b) and 457 plans is $24,500. The catch-up contribution limit for participants who are age 50 or older in 2026 is $8,000.
Maximum annual additions (i.e., employee deferrals, employer contributions and forfeitures) that can be allocated to a participant’s defined contribution plan account for 2026 is $72,000.
Limitation for the annual benefit under a defined benefit plan under Section 415(b)(1)(A) is $290,000.
The dollar amount used to define “highly compensated employee” under Section 414(q)(1)(B) is $160,000.
Newly eligible employees must receive a Summary Plan Description (SPD) within 90 days after becoming covered by the plan.
Provide quarterly statements and fee information to defined contribution plan participants.
Provide annual lifetime income illustrations to defined contribution plan participants.
Best Practices:
Contact your service provider or BDO’s ERISA team to discuss any required and/or discretionary SECURE 2.0 provisions effective in 2026 to ensure compliance. Check this article for a list of provisions that may impact your plan.
Make sure your Form 5330 is filed on time, as required, for any prohibited transaction reporting.
Make sure discretionary amendments that impact plan design and administration are executed and implemented timely per IRS regulations.
Make sure administrative procedures align with language in plan document.
Plans may consider doing mid-year compliance testing to avoid failing applicable annual tests.
Review and approve compliance testing results sent by plan administrator.
Plan sponsor should confirm the accuracy of the prior year’s census data to the recordkeeper. This information is used for ADP/ACP testing, among other things.
Some content borrowed with permission from BDO USA. Our firm is an independent member of the BDO Alliance USA, a nationwide association of independently owned local and regional accounting, consulting, and service firms.